This invention relates to a fastening device having positive locking means and, more particularly, to such a fastening device installed in a limited access environment such as that associated at the connection between a pair of hollow rotating shafts typically found in a gas turbine engine.
In certain areas of a gas turbine engine, it is extremely important that fastening means be positively secured. That is to say, bolts and the like, which are subject to engine vibrations and other cyclic forces, must be secured in their installed position lest they otherwise loosen during operation of the engine.
Positively secured fastening means have been the subject of prior activity. By way of example, U.S. Pat. Nos. 928,845; 1,333,742; 1,784,026; 3,016,077; and 3,561,516 all disclose various schemes for positively securing bolts in their installed position. It is observed that the devices described in these references contain a multiplicity of small hard-to-handle component parts. In a limited access environment, installation of these devices is tedious and difficult. In some instances, these component parts may be easily dropped during the installation or removal process and retrieval of the part is most difficult due to the poor visibility into the limited access location.
In other instances, the locking mechanism is located within the head or shank of the bolt and hence the mechanism must be comprised of many diminutive component parts which are difficult to manipulate in a limited accessibility area.
Additionally, these small component parts because of their size are fragile subject to easy breakage and lacking in rugged construction.
Therefore, it is an object of the present invention to provide a bolt having positive locking means for maintaining the bolt positively locked in an installed position.
It is another object of the present invention to provide a bolt having a positive locking means wherein the bolt and the locking means are of a rugged construction.
It is yet another object of the present invention to provide a bolt with positive locking means not having a multiplicity of separate component parts.
It is still another object of the present invention to provide a bolt with positive locking means which may be formed integrally with the bolt.
It is still yet another object of the present invention to provide a bolt with positive locking means disposed spaced apart or remote from the bolt itself.
Briefly stated, these and other objects which will become apparent from the following specification and appended drawings are accomplished by the present invention which provides for, in one form, a bolt having positive locking means comprising a generally cylindrical threaded portion and a headed portion proximate thereto. An elastically deformable annular ring portion is spaced apart from the headed portion and includes locking means disposed thereon which are adapted to selectively prevent rotation of the bolt in accordance with deformation of the ring. The annular ring is disposed in a first contour wherein the locking means prevents rotation of the bolt in an installed portion. The annular ring is deformable to a second contour wherein the bolt may be rotated to the installed position. A pair of connecting fingers connect the annular ring to the head of the bolt. The connecting fingers may be joined to the ring at the node points of the ring in the deformed mode. Additionally, the first contour may be elliptical.